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phil alvirez's blog
Posted by phil alvirez | Oct 28, 2014 @ 11:16 AM | 900 Views
as in the song 'the gambler', you need to know when to hold it, when to fold it, when to walk away, when to run,
so i am back into my other hobby: oil painting on canvas.
when it freezes and gets windy, i better watch for a rare chinook (you know, the warm weather from the north that sometimes blows in winter) to fly sometime during the day so it is warm enough for my bones, and not early in the morning.
in the meantime, i have something else to keep me busy.
i may bring some comments at the forums now and then, but otherwise you will not hear from me very much.
until next spring....
Posted by phil alvirez | Oct 27, 2014 @ 08:53 PM | 1,128 Views
i started a thread on the subject, trying to learn which 1 is better. at another forum i got data that allowed me to fully understand the differences. see: http://www.rcsoaringdigest.com/pdfs/...SD-1992-03.pdf (page 20). the point is that i wanted to know which is better and why, and now i got that. the most important thing is that, besides being more sensitive than stab/elevator, when giving 'down' commands it falls into negative decalage, that is, negative incidence respect to the wing, and that means unstable conditions, that may place the plane in critical situations.
i have been testing it, and have learned that the plane behaves erratic, i think due to this situation. there are also other factors that contribute to making this less convenient, and that is regarding to structure, as it is either fragile or heavier, tends to flex too much and vibrate, more difficult to build and repair, so i think i will stick with the conventional stab/elevator,
again, my view is that perhaps for full size airplanes that fly in transsonic regime it is not only better but necessary due to the shock wave near speed of the sound, but not for models.
Posted by phil alvirez | Oct 26, 2014 @ 12:17 AM | 1,071 Views
conclusions on trimming and decalage
the data that i have found the most precise on the issue was mentioned by mikeruth in his post 3919 of the forum of the radian: http://www.rcgroups.com/forums/showthread.php?t=2089760
he said: Page 20 of this article is a very good explanation of Setting decalage and CG.
I have been using this for years. http://www.rcsoaringdigest.com/pdfs/...SD-1992-03.pdf

the article was re-issued on 1992, and the copyright by Frank Deis is from 1990. it is the oldest i have ever seen on the subject, so the credit goes to him, and the flight test goes as far as 1973.
(by the way, the drawing has a mistake: in the rectangle at the left it says that cg is too far "forward" but should be "aft").
it shows how to do it and also shows tests on fixed stab and moving stabilator.
i will make a condensation of all that matters in that article. the goal is to have a decalage of about 1 to 3 degrees.
(decalage is the angular difference between the wing airfoil and the stabilizer).
this is the way i interpret it:
1.-start with a 33% balance point (called center of gravity);
test fly the plane:
2.-for a fixed stab (with moving elevator), trim the elevator until the plane glides well:
if the elevator is not parallel to the fixed stab, move the cg accordingly:
a.-if the elevator is up, move the cg back a little and try again until the elevator is parallel to the stab.
b.-if the elevator is down, move...Continue Reading
Posted by phil alvirez | Oct 25, 2014 @ 09:08 AM | 1,121 Views
Akin 45: a stretched super kinetic-see: http://www.hobbyking.com/hobbyking/s...dProduct=39853
the concept: i had the idea of using a hotliner, that is sort of a sailplane with clipped wings, to enhance its performance for soaring by enlarging its wing, as it has all that it takes to make a sailplane, including folding prop. got the super kinetic because has a good size and there is a spare wing available. the original wingspan is 32 inches (815 mm) and enlarged it to 45-1/2, and added some dihedral at the tips. 2 1.5mm cf rods at the sides near the nose to reinforce it, and also some carbon fiber veil to the nose and a piece of 2mm steel wire to the stab spar at the center. added area to the rudder. made an exhaust opening at the top of the canopy near the back to improve air flow to cool the motor and esc. i named it Akin 45 because it is a plane akin to the kinect, just longer wing. weight gain from extra wing is 34 grams, and wing area jumps from 130 to 194 sq in. weight without pack is 333 gr and with the 3x850 (72 gr) is 405. balances at 34 mm with the pack at the back of the canopy compartment. no ailerons to start, although i left the servos at the tips for a future use if needed, but i don't expect so. (then i will remove them and cover the slots). tested it and is erratic, as if the cg is too far forward, so i moved the pack to the under compartment an now balances at 39 mm. now is more predictable, but still more tests are needed. it is fast,...Continue Reading
Posted by phil alvirez | Oct 25, 2014 @ 09:01 AM | 1,124 Views
swift gull 35": a compact sailplane. the idea is to use parts already available and stretch the wing to make a sailplane-for soaring.
starting with parts for a mini-swift 24" http://hobbyking.com/hobbyking/store...dProduct=11306
plane: http://hobbyking.com/hobbyking/store...ider_PNF_.html
motor: http://hobbyking.com/hobbyking/store...or_1800kv.html
servos: http://www.hobbyking.com/hobbyking/s...cro_Servo.html
parts: http://www.hobbyking.com/hobbyking/s...0mm_Parts.html
esc: http://www.hobbyking.com/hobbyking/s...ontroller.html
pack: http://www.hobbyking.com/hobbyking/s...poly_Pack.html
prop: http://www.freakware.de/p/luftschrau...105-a66152.htm
well, i had the chance to fly it and needed a lot of up elevator trim, so i checked the decalage and it was 0-0. meaning that there is no angular difference between wing and stab. no good. and it balances at 33%. so i decreased the stab incidence and tested it. this time it came with a lot of down elevator trim so this means i went too far so i went back to half of the amount and this time came out with no trim, so this is the right decalage. finally! i have learned that some times foam planes misbehave because the fuselage is bent during manuacturing and their tail incidence is changed. also reduced the rudder area a little bit (that i increased before) as it was overly sensitive. the motor i used is not powerful but it climbs at about 30 degrees. if i can find a motor that is more powerful, weighs the same and is same dimensions, i will try it. it is fast, has a flat glide and handles wind well, and needs a good throw.
Posted by phil alvirez | Oct 24, 2014 @ 11:19 AM | 1,088 Views
an old sage once told me:
the key to happiness and success is learning to like what is good for you and what you have to do.
this way you also will be enjoying all of that and it will be easier and fun.

think about it.
Posted by phil alvirez | Sep 13, 2014 @ 05:39 AM | 2,442 Views
is left better?
when you study anatomy you realize that, as the heart is on the left side, you get more blood on that side. that's why the left foot is stronger and we climb horses or bikes leaning on the left leg-and why left hand baseball players hit stronger-and so boxers. but as we are programmed to use the right hand-or the majority follow it by impulse (1 of the mysteries of the mind)-the right hand becomes more dexterous due to that we use it more (practice). in industrial engineering, people is encouraged to use both hands by incentives-and so they learn to use them, and with practice they end mastering both. it is a matter of instructing your subconscious mind-which is a powerful ally. but as your left hand gets more blood, properly trained it can do better. and that is why when using both equally, it is stronger.
and, after all, if we fly r/c, we have to use both, right?
Posted by phil alvirez | Sep 10, 2014 @ 10:01 AM | 2,595 Views
the 1st time i flew in a full size airplane was in 1952, in a piper cub j3. it was at 6am because we were at 7,000 feet above sea level and at that altitude the air is so thin that it is better to start early, when the air has more density. when the instructor began to tell me: "this is the ground, this the air, this is the airplane", i told him that i was a student of aeronautical enginnering but had never flown before, and he stopped that. we had to fill the tank by hand, with car gasoline (in those days there was no high octanes-what was that?), neither airplane gas available. and we had to start by hand. but it was so much fun! the instructor was a short fellow, that had to add 3 cushions for him to see above the nose of the plane, and hardly could reach the pedals for the rudder. and no radio, so the control tower had to send a green light signaling that we were cleared for take-off. once we were flying, i began to familiarize with the controls. although i had a good idea of all, being there is another story. and then you get seasick. but was an unforgettable experience after all. we climbed and did whatever the instructor said, and after he saw that i was doing fine, we began the approach for landing, with me at the controls. as we were getting closer and he didn't took over i told him that i had no experience in landing, but he let me do it. what i did was throttling it down gradually and also pulling the elevator up slowly until i did a 3-...Continue Reading
Posted by phil alvirez | Sep 09, 2014 @ 08:12 AM | 2,567 Views
a silly question? but if asked 'are you left handed'? sounds right, isn't it?
we learn to use both feet the same. why not the hands?
i was born left handed (got that from my father) and when i got to school they forced me to learn to use the right hand. that was the way in those days. so i learned to use it. my writting was-is-awful, so they say, and also they say that it is due to having been lefty and pushed to be righty. but my writting with the left is as bad. but when i broke my right arm, again i had to write with my left. after that, i decided to learn to use both hands, and became ambidextrous. but, why not? using 1 hand we use only 1 half of the brain, so why not teach the other half? there is room there for this. we do this with our legs, otherwise when we walk we would limp all the time. now, that sounds silly, isn't it?
so, are you left-footed? think about it.
Posted by phil alvirez | Sep 01, 2014 @ 10:04 AM | 2,513 Views
conclusions on ap vs no ap-my view.
1.-i am pleased with the rad as is, with the autopilot (ap), and from what i read, many others too. http://www.rcgroups.com/forums/showthread.php?t=2089760
and still there are some who think it is better without it. i think that with ap in windy weather (for which it was intended) it does much better.
2.-anyway, as the brick of 1 of my rads went south and don't have another of the same ap, i replaced it with 1 that has no ap (AR6400), so will try and compare in no wind days. some say that without ap it thermals better.
3.-well, there was a window in the weather and had the chance to evaluate the conversion.
the plane flies fine in calm, although behaves different, as could be expected. problem was, that could not evaluate it completely because the prop does not stop, even if stalling the plane.
4.- i added the esc that helps to stop the prop. it is done, so only i have to wait until next window again.
5.-now i was able to try it: with little wind it is a lively plane: sensitive, responsive, but still controllable, so it behaves just as any other plane of its size. and in no wind it is a lively nice little plane. still i have to try it in no wind thermals to see how it behaves.
so in some wind with no ap, it needs frequent commands, as any other plane its size.
and another identical plane with ap is way more stable, self-compensating for the drafts.
big difference. but it's up to each 1 which way you like it.
it confirms that only with ap it can be flown in windy weather that otherwise only larger planes can do, and in smaller places.
Posted by phil alvirez | Aug 27, 2014 @ 11:52 PM | 3,812 Views
some say that the early years were their happiest. i wonder...
i recall being told what to do and what not to do. then being taken to a place full of rascals that were doing their best to make my life miserable, and a grownup telling me what to do. things that i already knew, or i didn't care. that was called school. sometimes the grownups brought me with my cousins (a bunch of wild beasts) to a large tent, smelling heavily of manure, full of people, where there were some huge grey animals that looked like rocks (called elephants), some horses and fellows doing wild stunts, and other hanging from swings. the only thing i liked were the beautiful girls that did stunts on swings. the place was called the circus. other times they brought me to a sunny place where a fellow dressed like a clown entertained a bull with a piece of canvas. later a fellow on a horse pierced the back of the bull with a pike, and another challenged the bull with some sticks that managed to place on the back of the bull. then the clown killed the bull with a sword and 2 horses dragged the carcass away. that was called bullfighting. i also heard that my father was an amateur boxer, and he sometimes went to exchange punches with another 1. that was called boxing, but i was lucky enough not to be taken there because that happened too late in the evening for me. and grownups always so full of themselves, and making practical jokes on me.
and some wondered why i liked to be by myself!
Posted by phil alvirez | Jul 20, 2014 @ 10:05 AM | 4,221 Views
right of way
1 of the great things of living in places like the grey wild north is that we have frequent encounters with wild life, be in large cities or in the middle of nowhere.
1 episode that i just lived happened on my way from the park where i fly my lil radian:

when i was driving back home i noticed that the cars had stopped-both ways of the road- and didn't see any reason why, until got closer: it was a single goose that was on the road, but not walking. it was at the edge of the park, where a pond is located, and seemed like hesitating; looking towards the pond and the other way. then i noticed that there was a flock of about 20 geese near him, still on the grass, looking at him, that also were hesitating. they were trying to cross the road to reach the pond nearby. then i saw what was the reason of their hesitation: there was a girl with a dog walking around the pond, in the direction where they were aiming at. it was not until she went far that the goose started walking towards the pond. slowly, no hurry. calling the others. and then the others followed. it was until all were safe at the grass, that we started driving. it is amazing to see how they know that they have the right of way-and we have to accept that.
but after all, they were here before, isn't it?
Posted by phil alvirez | Jul 18, 2014 @ 09:28 AM | 3,887 Views
july 17: at 5:30 am took the lil rad (umx radian) http://www.rcgroups.com/forums/showthread.php?t=2089760 to the nearby park (the pond). some wind, but great time anyway. then came back at 8:00. more flying. even got into a thermal. then went to my son's nearby for a while. then we were going shopping, but as i had the planes with me, i asked him to get the camera and film me flying at the street. but when i tried to land, the plane was overshooting, as the glide was too flat and didn't want to come down. i realized it was sloping at the houses roofs. so i had to overshoot instead of catching it. landed a little bit ahead on the street. this thing can fly almost anywhere!
Posted by phil alvirez | Jul 04, 2014 @ 08:01 PM | 4,518 Views
today i had the pleasure to get my micro radian into a thermal for the 1st time. http://www.rcgroups.com/forums/showthread.php?t=2089760
i fly usually at dawn, as it is when i find a window in the wind, but today at 8:00 pm i looked into the window and noticed that all the trees were still, so got my rad and radio and ran to the pond nearby (10 minutes/6 km), and launched the plane. after several uneventful but pleasant flights in a blue sky without clouds, when i had done 4 minutes of motor, on the last run, noticed that it was not coming down. as usual, i was turning, so kept doing it, but after some time it was getting too high and small and drifting too far, so i brought it back. but it was a wonderful experience!
i had flown the rad consistently, but at dawn there are no thermals-at last i have been unable to detect 1-and also have flown many planes of all kinds into thermals, but with this little wonder i have the oportunity to try it at places nearby, even with some wind, so it expands my horizons enormously.
to all of you who already have got your lil rads into thermals, you understand the feeling.
and to all of you who still haven't, i dedicate this, with the best wishes that some time you will also enjoy the feeling.
it's a wonderful life.
Posted by phil alvirez | Jun 30, 2014 @ 07:37 AM | 4,744 Views
biking in vancouver, british columbia.
in the 80's i lived in vancouver-and had a hobby shop at kingsway street-and also got a motorcycle (a yamaha vision with touring fairing, shaft drive and water cooled). when the weather was good, i toured around. with so many beautiful places nearby, it was a most rewarding experience. as there are many rivers that have no bridges, there are ferries to cross, and boarding them with the bike was thrilling, to say the least. just entering and exiting the ferry was exhilarating, riding through any of the 2 narrow ramps and seeing the water below.
even just going downtown and watching the sunset at english bay and eating a souvlaki at davie and denman street. and all were so watchful on bikes.
we flew r/c at kitsilano, with the sailplanes flying over the sea most of the time. and stanley park: the beavers taking off right there (i mean, the de havilland airplanes) on their way to victoria island... also going to victoria by ferry with the bike. i still have the bike in my living room, but don't ride anymore. am sending it to my son's garage soon to make room for my toys (model airplanes and painting). so many memories....
Posted by phil alvirez | Jun 20, 2014 @ 08:44 AM | 4,879 Views
when you grow old, more frequently you say 'those were the days' and recall episodes of your life when things were better. as some say, all things past were better. right?
well, now that i have my micro rad and just pick it up and the radio and place it at the back of my car and drive 10 minutes, or when on my way shopping i drive to the park, launch it and have a ball for several minutes, i think, well, these are the days! nothing past can compare with the fun am having now. life is good. enjoy.

http://www.rcgroups.com/forums/showthread.php?t=2089760
Posted by phil alvirez | Jun 13, 2014 @ 05:51 AM | 5,031 Views
the reason why am happy and have enjoyed life is because am a dreamer.
yes, i live in fantasyland. and the good thing of this is that nothing can reach me.
some1 said that there are 2 things that no1 can take away from you: your memories and your dreams.
others call me mad, because they say that i should see things the way they are, but if you live in reality, just look around.
could you be happy with that?
as Cervantes in "Man of la Mancha" said: 'who is the maddest of all, he who sees things the way they should be, or he who sees things they way they are?'
your choice.
and i think that the way to improve things is seeing them the way they should be. that's the value of daydreaming.
Posted by phil alvirez | Jun 05, 2014 @ 07:22 AM | 5,454 Views
since i remember, anything that flies has fascinated me. birds, butterflies, any insect, and of course airplanes. full size or models. even watching the clouds go by. from the beginning of time, it has been the wildest dream of humans. that's why all the legends, tales and fantasies. i feel as if i were the plane or bird, or if my spirit were up there with it. from the times when there was only free flight. and now with the magic of radio control, when i can maneuver it, even soaring into thermals, is the realization of my wildest dream. and i believe that many more share this feeling.
be that you design it, or build it, or even now with the ready-to-fly, all leads to the ultimate goal: flying it.
so, let's dream of flying, the most wonderful adventure.
Posted by phil alvirez | May 31, 2014 @ 05:52 AM | 6,100 Views
swan lake
with a title like this, you may think of me as a romantic.
if you do so, you are right.
but there are things that go beyond a logical explanation.
i have been to a park nearby that has a pond where geese and swans make a home during the good weather.
in recent posts i mentioned that 1 morning when i was arriving, a couple of white swans landed. they could arrive before-or after-but why exactly when i was arriving? symbolic, isn't it? silent, majestic creatures. anyway, shortly after that, a flock of geese arrived. all noisy, honking their lungs in happy celebration, even after landed, for several minutes. then another flock. and another. soon the pond was crowded with happy birds.
i have seen the swans several years at the pond. seems that it is their residence for the good weather. but once there, they don't fly anymore, contrary to the geese, that every morning leave noisily, flock after flock. the swans occasionally swim slowly around, but most of the time they just rest.
so, now that am back into micros, and fly at the lake, sharing it with the birds is a great experience.
Posted by phil alvirez | May 26, 2014 @ 10:45 AM | 5,237 Views
am doing field tests to have an idea of how much time we have available for thermaling with the micro radian.
as there are not (yet) means to get figures or warnings in the stock plane, these are estimates based on flights measuring the time of the motor runs and flight times, and then checking how much charge the cell had and the % it had left.
if we run the motor to climb as high as we still can control the plane and see what it is doing, then stop it (and time it), and do this several times (accumulating the time) until it slows down because the cell is reaching the point where it drops, and check the charge left (and its %), and doing other flights with same (or similar capacity) cell but then stopping before this happens, gradually less and less time, and checking charge and %, we can get an idea of when to stop using the motor and still have a reserve of power for thermaling. nothing exact, but a reasonable estimate.
cells used are from stock hobby king, and horizon 25 and 45c.
from these tests i have found that stopping the motor from 4 to 4:30 minutes total time, there is still about 20% charge (3.75v), and this could give a reasonable time for thermaling, considering that it takes little power using just the servos. and if we trim the plane to circle without sinking, there is no need for correcting and the draining the cell is very little. if going to 5-5:30 minutes, the charge drops to 9-10% (3.5v), but this could be considered too low.
how long before the plane runs out of power and goes free flight? hard to say unless getting into thermals and checking the time and then bringing it down and measuring the charge left.
i got some advice regarding this, that can be of good use: Daedalus66 said: One answer is simply to use a little burst of power from time to time. If the motor shuts down or refuses to start, it's time to land. (and i add: that is, if the plane is not so far that you can see this). so there you have it.